The long-term goal of this project is to understand the mechanism(s) regulating cell proliferation, growth and tissue repair in the mammalian lens. We hope to gain some insight into the mechanism by which transparency is restored in the traumatized lens. Such data may have significance in ophthalmology and in other fields of biomedical science in which the control of mitosis and growth plays an important role. We plan to define the conditions required for the establishment of continuous lines of human lens epithelial cells. The influence of insulin, insulin-like growth factors, steroids and specific components of the medium will be determined in an effort to characterize the environmental conditions that determine whether the cells divide, differentiate or become senescent. Slab-gel electrophoresis coupled with autoradiography will be used to ascertain the presence of lens-specific proteins. Additional aims are to: characterize the mitogenic factor(s) in the aqueous of normal and traumatize eyes, determine the amount of insulin in the aqueous by radioimmunoassay, evaluate the mitogenicity of insulin-like factors on the lens cells in organ and tissue culture, determine the components in the medium that act in concert with certain peptides to induce mitosis, characterize insulin receptors in human and rabbit lens cells and determine the localization of insulin in the lens at the ultrastructural level. We plan to determine in steroids or proteases (thrombin) potentiate the mitogenic response engendered by specific growth factors and determine the effect of steroids on wound-related mitosis in the lens in vivo. Attention will also focus on changes in macromolecular synthesis and on ultrastructural changes that may characterize the newly stimulated cells. Cytochemical techniques will be used to monitor changes in the localization and magnitude of the reaction products for acid and alkaline phosphatase, Na ion/K ion-ATPase, phosphodiesterase and in the cell surface that may occur in cultured cells or subsequent to traumatic insult to the lens in situ.